JP2001327139A - Hub dynamo for bicycle and the bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hub dynamo for bicycle which can reduce the magnetic reluctance of a stator core and can improve power generation efficiency by suppressing generation of an eddy current, and a bicycle loading the same hub dynamo. SOLUTION: In a hub dynamo for bicycle comprising two stator cores 16, 17, in which a permanent magnet 14 is arranged on the inside of a hub body 12 and a plurality of pole pieces opposing the magnetic poles of the permanent magnet 14 are provided on the circumference of a hub shaft 10, and a coil 22 wound around a coil bobbin 20 arranged between these stator cores 16, 17, the stator cores 16, 17 are magnetically coupled with a cylindrical core 18 on the side of hub shaft and one or a plurality of slits 24 are opened in the direction parallel to the hub shaft 10 at the outer circumferential surface of the core 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a core of a hub dynamo for bicycle power generation.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. Hei 7-291166 (B62J6 / 12) discloses a hub dynamo for bicycle power generation.
As shown in FIG. 7, the hub axle (10) of the front wheel or the rear wheel of the bicycle
A pair of stator cores (90) and (91) are provided, and a coil bobbin (20) around which a generator coil (22) is wound is accommodated inside the stator cores (90) and (91) to form a stator, and a hub shaft A hub dynamo (93) in which a rotor is formed by disposing a permanent magnet (14) opposite to the stator on a hub body (12) rotatably supported with respect to (10) is disclosed. The permanent magnet (14) is configured such that N poles and S poles are alternately arranged in the circumferential direction (see FIG. 2), and the stator cores (90) and (91) face either the N pole or the S pole on the outer periphery thereof. The magnetic pole pieces are projected at the pitch of the poles of the permanent magnet (14). Therefore, one stator core (90)
Is facing the north pole of the permanent magnet (14), the other stator core (91) faces the south pole, and the north pole → stator core (90)
→ Connection with hub shaft (10) → Stator core (91) → Form magnetic path of S pole. The electrical end of the generator coil (22) is connected to a bicycle lamp (not shown) via a lead wire (72) or the like.

The power generation of the hub dynamo (93) is performed in the following manner. That is, when the wheel is rotated, the permanent magnet (14) attached to the hub body (12) that rotates integrally with the wheel rotates. The magnetic flux emitted from the permanent magnet (14) has a state in which one of the opposed stator cores (90) and (91) has an N pole and the other has an S pole,
A state in which one is an S pole and the other is an N pole is alternately repeated to generate an alternating magnetic flux in a magnetic path. The alternating magnetic flux generated inside the power generation coil (22) causes a current to flow through the power generation coil (22) to generate power.

The alternating magnetic flux generated in the stator cores (90) and (91) is, as shown by arrows in FIG.
Go around. The stator cores (90) and (91) are at the center, that is,
Since the stator cores (90) and (91) are connected to each other on the fixed side with respect to the hub shaft (10), there is a problem that the magnetic resistance is large at the connection portion. Therefore, in the above publication, the stator core (90) (9
1) To reduce the magnetic resistance between the stator core (90)
As shown in FIG. 7, a cylindrical auxiliary core (9
4) is provided to reduce the magnetic resistance at the joint between the stator cores (90) and (91).

[0005]

SUMMARY OF THE INVENTION Stator cores (90) (91)
, An eddy current is generated with the passage of the alternating magnetic flux. Since the eddy current reduces power generation efficiency, it is necessary to suppress the generation of the eddy current as much as possible.However, in the hub dynamo (93) having the above configuration, the As the amount of magnetic flux passing increases, the generated eddy current also increases, making it impossible to sufficiently improve power generation efficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bicycle hub dynamo capable of reducing the reluctance of a stator core and suppressing the generation of eddy current to improve the power generation efficiency, and a bicycle equipped with the same. is there.

[0007]

In order to solve the above-mentioned problems, a bicycle hub dynamo (3) according to claim 1 of the present invention is provided.
In (2), a permanent magnet (14) is arranged inside a hub body (12), and a plurality of pole pieces facing the magnetic poles of the permanent magnet (14) are provided on the hub shaft (10). In a bicycle hub dynamo comprising a stator core (16) (17) and a coil (22) wound around a coil bobbin (20) disposed between the stator cores (16) (17), the stator core (16) (17) is magnetically coupled by a cylindrical core (18) on the hub shaft side, and the core (18)
One or a plurality of slits (24) are formed on the outer peripheral surface in a direction parallel to the hub shaft (10).

In the bicycle hub dynamo (30) according to the second aspect of the present invention, one of the slits formed in the core (18) is inserted into one of the slits (26) up to the inner surface of the core (18). And is circumferentially separated at a part of the core (18).

In the hub dynamo (30) for a bicycle according to the third aspect of the present invention, the core (18) is made of a powdered sintered material or a pure iron-based soft magnetic iron material.

Further, in the bicycle hub dynamo (30) according to a fourth aspect of the present invention, the coil bobbin (20) is provided with a rib (28) projecting inward, and the rib (28) is connected to the core ( The core (18) is positioned with respect to the coil bobbin (20) by fitting the slit (24) and / or the slit (26) formed on the outer peripheral surface of the coil (18).

According to a fifth aspect of the present invention, there is provided a bicycle hub dynamo (30), wherein the bicycle hub dynamo (30) comprises a hub body (1).
A permanent magnet (14) is arranged inside 2), and a hub axle (10)
Two stator cores (16) and (17) provided on the periphery with a plurality of pole pieces facing the magnetic poles of the permanent magnet (14);
(17) Coil wound around coil bobbin (20)
(22), wherein the stator cores (16) and (17) are magnetically coupled by a cylindrical core (18) made of powdered sintered material on the hub shaft side. is there.

According to a sixth aspect of the present invention, there is provided a bicycle hub dynamo (30), wherein the bicycle hub dynamo (30) comprises a hub body (1).
A permanent magnet (14) is arranged inside 2), and a hub axle (10)
Two stator cores (16) and (17) provided on the periphery with a plurality of pole pieces facing the magnetic poles of the permanent magnet (14);
(17) Coil wound around coil bobbin (20)
(22), the stator cores (16) and (17) were magnetically coupled on the hub axle side by a cylindrical core (18) made of a pure iron-based soft magnetic iron material. Things.

[0013] The bicycle (40) according to claim 7 of the present invention comprises:
The hub dynamo (30) according to any one of claims 1 to 6 is mounted on a front wheel or a rear wheel, and the hub dynamo (30) is electrically connected to a headlight (46) and / or a taillight. It was done.

[0014]

The bicycle hub dynamo (30) according to the first aspect of the present invention has a slit (24) (2) on the outer peripheral surface of the core (18).
6) is opened, the core (18) is slit (24) (2
6) is electrically insulated in the circumferential direction. For this reason, the eddy current flowing in the circumferential direction of the core (18) can be cut off by the slits (24) and (26), and improvement in power generation efficiency can be achieved. Therefore, the size and weight of the hub dynamo (30) can be reduced, and the torque required for power generation can be reduced.

According to a second aspect of the present invention, there is provided a bicycle hub dynamo (30), wherein a cylindrical core (18) is provided with one through slit (2).
By separating the core (18), electrical insulation in the circumferential direction of the core (18) can be completed. Therefore, the generation of eddy current flowing in the circumferential direction of the core (18) is greatly reduced, and the power generation efficiency can be further improved.

Further, in the bicycle hub dynamo (30) according to the third aspect of the present invention, the core (18) is made of a powdered sintered material having a low magnetic resistance or a pure iron-based electromagnetic soft iron material. Since the attenuation of the magnetic flux can be suppressed, the power generation efficiency can be improved.

According to a fourth aspect of the present invention, there is provided a bicycle hub dynamo (30), wherein the core (18) is connected to the hub shaft (10) or the coil bobbin.
Instead of directly fixing the core (18), the rib (28) protruding from the inner surface of the coil bobbin (20) is fitted with the slit (24) and / or the slit (26). Because the bicycle is positioned, even if a shock is applied to the core (18) by the vibration of the bicycle, the impact force is absorbed by the ribs (28) compared to the case where the core (18) is directly fixed to the hub axle (10). The force is not easily applied to the core (18), and the damage of the core (18) is prevented. In particular, when the core (18) is made of powdered sintered material, the powdered sintered material is
Although it is hard and brittle, breakage can be effectively prevented by suppressing the stress generated in the core (18).

Further, in the bicycle hub dynamo (30) according to the fifth or sixth aspect of the present invention, the core (18) is made of a powder sintered material having a low magnetic resistance or a pure iron-based electromagnetic soft iron material. Therefore, the power generation efficiency can be improved and the hub dynamo (30) can be downsized.

A bicycle according to a seventh aspect of the present invention is equipped with a hub dynamo (30) having excellent power generation efficiency as a generator, a torque required for power generation is small, and a hub dynamo (30) is provided. Because it is possible to reduce the size of the bicycle, it is possible to reduce the weight of the bicycle and reduce the stepping force of the bicycle necessary for power generation.

[0020]

FIG. 1 shows a hub dynamo (3) of the present invention.
0) is a cross-sectional view including the hub axis direction, and FIG.
FIG. 3A is a sectional view taken along the line II-II, and FIG.
7) is a side view, FIG. 3 (b) is a front view of the stator core, FIG.
(a) is a side view of the core (18), FIG. 4 (b) is a front view of the core (18), and FIG. 5 is a bicycle (40) on which the hub dynamo (30) is mounted.
2 shows an enlarged view of the front wheel portion of FIG.

The hub dynamo (30) of the present invention is a bicycle (40).
Is mounted on the front wheel portion or the rear wheel portion. Hereinafter, an example in which the hub dynamo (30) is mounted on the front wheel side will be described.
As shown in FIG. 5, the bicycle (40) has a hub axle (10) rotatably supporting a front wheel (42) attached to a front fork (44), and is disposed on a side of the front wheel (42). Headlights (4
6) and power to tail lights (not shown) arranged on the rear wheel side. The front fork (44) is supported by the body frame (48), and a handle (50) and a front basket (52) are attached to the upper end of the front fork (44).

As shown in FIG. 1, both sides of the hub axle (10) are fixed to front forks (44), (44).
(0) has a cylindrical hub body (12) through bearings (54) and (54).
Are rotatably provided. A plurality of spokes (56) are attached to the hub body (12), and the outer periphery of the spokes (56) is provided with a tire (6) via a rim (58) as shown in FIG.
0) is attached.

A stator is provided on the hub shaft (10).
As shown in FIG. 1, the stator includes a cylindrical core (18), a coil bobbin (20), a power generation coil (22), and a pair of stator cores (16) and (17).

The core 18 is, as shown in FIGS.
A plurality of slits (24) and (26) are formed inward from the outer peripheral surface. In order to reduce the magnetic resistance of the core (18), it is desirable that the thickness of the core (18) in the radial direction be 7 to 9 mm. It is desirable to be formed from a material. By forming the core (18) to be thick, the cross-sectional area of the core (18) can be increased, and a reduction in magnetic resistance can be achieved. The slit (24) formed in the core (18) preferably has a depth of 6 to 7 mm, and one slit (26) is formed so as to reach the inner surface of the cylinder and is electrically insulated in a circumferential direction. Is desirable.

A coil bobbin (20) around which a generating coil (22) is wound is fitted around the outer periphery of the core (18). Generator coil
One of the electrical ends of (22) is connected to a headlight (46) via a lead wire (72), and the other is directly connected to a hub axle (10) or the like. Headlight via (44) (4
6) is electrically connected. The coil bobbin (20) can be made of a resin material, and as shown in FIG. 1, an annular body having a U-shaped cross section opened toward the outer periphery can be exemplified. As shown in FIG. 2, one or more ribs (28) are provided on the inner peripheral surface of the coil bobbin (20).
Is fitted with the slit (24) and / or the slit (26) of the core (18), and the core (18) is stopped and positioned.

The stator core (1) is provided on both left and right sides of the core (18).
6) (17) is deployed. As shown in FIGS. 3 (a) and 3 (b), the stator cores (16) and (17) have a large number of inwardly bent magnetic pole pieces (74) and (75) protruding from the outer periphery of a disk body (80). It is.
The pole piece (74) is a pole piece (75) of the opposing stator core (17).
Are formed so as to have equally spaced gaps. The stator cores (16) and (17) can be made of a rolled steel material for general structure. It is desirable that the disk body (80) of the stator cores (16) and (17) be cut out (76) from the center toward the outer circumference to suppress the generation of eddy current generated in the stator cores (16) and (17). A lead wire (72) extending from the power generation coil (22) can be passed through the cut (76).

The stator is a coil bobbin in which a core (18) and a power generation coil (22) are accommodated between stator cores (16, 17).
After the (20) is sandwiched and passed through the hub axle (10), it can be attached to the hub axle (10) by fastening with bolts (81).

A rotor is provided in the hub body (12). The rotor is a pole piece (74) (7) of the stator core (16) (17).
The number of permanent magnets (14) corresponding to the number of (5) is arranged in the circumferential direction, and the permanent magnets (14) are arranged so that the inner surface alternately has N poles and S poles.

With the hub dynamo (30) having the above configuration, when the bicycle (40) is run and the wheels (the front wheels (42)) are rotated, the rotor rotates with respect to the stator. as a result,
Permanent magnets outside the pole pieces (74, 75) of the stator cores (16, 17)
(14) moves.

When the pole piece (74) of one stator core (16) faces the N pole of the permanent magnet (14), the pole piece (75) of the other stator core (17) is Facing the south pole,
As shown by the arrow in FIG. 1, the pole piece (74) of one stator core (16) → the disc body (80) → the core (18) → the disc body (80) of the other opposing stator core (17) → the pole piece A magnetic flux passing through (75) is generated. Further, the front wheel (42) rotates, and one of the stator cores (1
The pole piece (74) of (6) faces the south pole and the other stator core (17)
When the pole piece (75) faces the N pole, the pole piece (75) of the stator core (17) → the disc body (80) → the core (18) → the disc body of the opposed stator core (16) (80) → A magnetic flux passing through the pole piece (74) is generated. As the front wheel (42) rotates, the stator core (1
6) When the poles of the permanent magnet (14) facing the pole pieces (74) and (75) of (17) change, the magnetic flux is generated alternately and becomes an alternating magnetic flux.

An alternating magnetic flux passing through the stator cores (16) (17) and the core (18) generates a current in the power generating coil (22), thereby generating power.

At this time, an eddy current is generated in the core (18) by the alternating magnetic flux passing through the core (18).
Since the current flow in the circumferential direction of the core (18) is interrupted by the slits (24) and (26) opened on the peripheral surface of (18),
No eddy current flows in the circumferential direction of the core (18). Therefore, generation of eddy current can be suppressed, and reduction in power generation efficiency due to eddy current can be prevented.

[0033]

EXAMPLE A core (18) was prepared by changing the number of slits (24) and (26) to be opened and the material, and each was incorporated into a hub dynamo (30) to compare the power generation voltage. Core shape is 26m outside diameter
As shown in FIG. 6, slits (24) and (26) were opened in a cylindrical shape having a diameter of 9 mm, an inner diameter of 9 mm and a length of 21 mm. The number of slits (24) and (26) opened in the core (18) is zero as shown in FIG.
(Slot 1), 1 (slot 2), 2 (slot 3),
There were four (slot 4), eight (slot 5), and twelve (slot 6). As shown in Table 1, the material of the core (18) was made of a general mild steel material having a low carbon content (rolled steel material for general structure SS400 (SS41)) for the slots 1 to 6, and these slots were subjected to annealing heat treatment. Was given. Note that slot 1 is a comparative example. For the slots 1 and 2, cores were further prepared from pure iron-based electromagnetic steel materials (electromagnetic soft iron SUYB0 to SUYB3) and ferrite-based powder metallurgy magnetic materials (iron oxide-based soft magnetic materials).

The measurement conditions are as follows.・ Rotation speed of wheels: 120rpm (15km with 26 inch wheels)
/ Equivalent to / h)-Stator core: T2.3 SPCC, annealing, cutting
(76) (See Fig. 3) ・ Generating coil: φ0.65mm × 325 turns

The results are shown in Table 1. The power generation voltage is shown as a relative value when the slot 1 of the ferrite powder metallurgy magnetic material is set to 100.

[0036]

[Table 1]

Referring to Table 1, with respect to a core made of a general mild steel material, a slit is formed to form a core.
It can be seen that the generated voltage has been improved. However, for the slot 6 in which 12 slits are opened,
It is inferior to the slot 5 opened individually. This is because if the number of slits is too large, the magnetic resistance increases. Therefore, it is understood that the number of slits to be opened is suitably 1 or more and 12 or less, and more preferably 2 or more and 8 or less. In particular, if the number of slits is 4
The number of the slots 4 and 5 is approximately equal to that of a pure iron-based electromagnetic steel material. As described above, by adjusting the number of slits, an inexpensive general mild steel material having excellent workability can be used as a high-performance core.

It can be seen that both the slots 1 and 2 made of pure iron-based electromagnetic steel and ferrite-based powder metallurgy magnetic exhibit high power generation efficiency. This is because the use of a material having a low magnetic resistance and a low electrical conductivity can suppress the generation of eddy current while generating an alternating magnetic flux.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a sectional view including a hub shaft of a hub dynamo of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II of FIG.

FIG. 3A is a side view of a stator core, and FIG. 3B is a front view of the stator core.

4A is a side view of the core, and FIG. 4B is a front view of the core.

FIG. 5 is an enlarged view of a front wheel portion of a bicycle equipped with the hub dynamo of the present invention.

FIG. 6 is a side view of a core of slots 1 to 6 used in the embodiment.

FIG. 7 is a cross-sectional view including a hub shaft of a conventional hub dynamo.

[Explanation of symbols]

 (10) Hub shaft (12) Hub body (14) Permanent magnet (16) Stator core (17) Stator core (18) Core (20) Coil bobbin (22) Coil (24) Slit (26) Slit (30) Hub dynamo

Claims (7)

[Claims] 1. A permanent magnet (14) is arranged inside a hub body (12), and a plurality of pole pieces facing the magnetic poles of the permanent magnet (14) are provided on the hub shaft (10) on the periphery. Two stator cores (16, 17)
And a coil bobbin disposed between the stator cores (16) and (17).
In a bicycle hub dynamo comprising a coil (22) wound around (20), a stator core (16), (17) has a cylindrical core (18) on the hub shaft side.
The core (18) has one or more slits in a direction parallel to the hub shaft (10).
A hub dynamo for bicycles, characterized by the establishment of (24). 2. A slit formed in the core (18),
One slit (26) reaches the inner surface of the core (18),
(1) A part of (18) is circumferentially separated.
The dynamo for a bicycle described in 1. 3. The hub dynamo for a bicycle according to claim 1, wherein the core is made of a powdered sintered material or a pure iron-based soft magnetic iron material. 4. The coil bobbin (20) has ribs (2
8) is projected, and the core (18) is fitted to the coil bobbin (20) by fitting the rib (28) into slits (24) and (26) formed on the outer peripheral surface of the core (18). The bicycle dynamo according to any one of claims 1 to 3, which is positioned with respect to the bicycle hub dynamo. 5. A permanent magnet (14) is disposed inside a hub body (12), and a plurality of pole pieces facing the magnetic poles of the permanent magnet (14) are provided on the hub shaft (10). Two stator cores (16, 17)
And a coil bobbin disposed between the stator cores (16) and (17).
In a bicycle hub dynamo comprising a coil (22) wound around (20), a stator core (16) (17) has a cylindrical core (18) made of powder sintered material on the hub shaft side. ), The hub dynamo for a bicycle being magnetically coupled by: 6. A permanent magnet (14) is arranged inside the hub body (12), and a plurality of pole pieces facing the magnetic poles of the permanent magnet (14) are provided on the hub shaft (10). Two stator cores (16, 17)
And a coil bobbin disposed between the stator cores (16) and (17).
In a bicycle hub dynamo comprising a coil (22) wound around (20), a stator core (16) (17) is a cylindrical core made of a pure iron-based electromagnetic soft iron material on the hub shaft side. A bicycle hub dynamo magnetically coupled by (18). 7. A hub dynamo (30) according to any one of claims 1 to 6 mounted on a front wheel or a rear wheel, and the hub dynamo (30) is mounted on a headlight (46) and / or a taillight. Bicycle electrically connected to.